P374 Disease course and fate of Crohn’s perianal fistula patients following failure of initial biologic therapy: real-world lessons on the impact of refractory disease from a tertiary centre cohort
S. Adegbola, W.Y. Mak, K. Sahnan, S. Hiles, P. Bassett, P. Lung, J. Warusavitarne, O. Faiz, R. Phillips, P. Tozer, A. Hart
Department of Colorectal Surgery, St. Mark’s Hospital, Harrow, UK
Background
Current evidence demonstrates that anti-TNF therapies lead to clinical response rates >50% have been reported in the short-term. These remission rates decrease to about a third of patients who initially achieved remission, after three years. Options are limited in cases refractory to biologic therapy, and there is limited knowledge of disease course in these cases, in part due to limited disease states characterised for Crohn’s perianal fistula in the absence of cure. This study applies recently described disease states within the context of Crohn’s perianal fistula to determine the fate of patients refractory to initial biologic therapy and quantitatively evaluate the health resource impact of the loss of response to treatment in this cohort.
Methods
Retrospective review of records from patients undergoing anti-TNF treatment for Crohn’s perianal fistula at St Mark’s Hospital between January 2007–December 2016, identified those refractory to treatment. We applied disease states defined from a recent vignette study of the general public and CD patients in the UK, and also obtained data on length of time patients spent in each disease state and subsequent disease states they transitioned to and created a Markov model to assess transition probabilities. We also collected data on healthcare resource utilisation (MRI, hospital interactions, surgical/medical therapy) within each disease state.
Results
Eight fistula disease states (including proctectomy, defunctioning surgery, remission and symptomatic states) were retrospectively ascribed to all clinical records/visits where documentation was available. The majority of refractory patients were switched on to alternate anti-TNF therapy and most reside in a ‘mild chronic symptomatic fistula’ disease state with a minority of patients subsequently transitioning into a severe disease state or remission state. Successful proctectomy disease state accounted for the longest period of continuous length of time in any one disease state (mean 4.4 years). The overall remission rate (of any duration) for our study cohort of 78 patients was 46%; however, sustained (1year or more) remission rate was 27%. Some 19% patients underwent proctectomy. There was considerable healthcare resource utilisation amongst all disease states particularly with biologic therapy (most expensive healthcare resource).
Conclusion
Whereas most patients reside in a mild chronic state following failure of at least one biologic therapy, a fifth of patients refractory to treatment undergo proctectomy which, when successful, accounts for the longest continuous length of time patients spend in a single disease state. There remains considerable healthcare resource utilisation and better treatment options are needed in refractory patients.